Cluster arrangement



2 Sheets-Sheet 1 Aug. 19, 1969 1'. RASTELLI CLUSTER ARRANGEMENT Filed Dec. '29,v 1966 Aus- 19, 1969 T. msm-LLI 3,461,104

CLUSTER ARRANGEMENT Filed Dec. 29. 1966 2 Sheets-Sheets v FTQ 7.

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ATTORNEYS United States Patent O U.S. Cl. 72-242 10 Claims ABSTRACT F THE DISCLOSURE A cluster mill arrangement useful in the rolling` of sheet or strip from stock, wherein the work roll si'zes may be interchanged without the necessity for changing the mill housing or drive stand and without necessitating the change of a large number of rolls in the arrangement, consisting of a pair of work rolls; two pairs of intermediate rolls in contact with said work rolls; two pairs of back-up rolls wherein each back-up roll is in contact with the corresponding intermediate roll; a pair of center rolls which are in contact with each pair of intermediate rolls and directly above and -below the work rolls; and a pair of auxiliary back-up rolls in contact with the corresponding center roll. Either the work rolls or the center rolls may be driven.

This invention relates to rolling mills for rolling strip and sheet and more particularly to multi-high mills having a particular roll cluster arrangement.

In the prior art there are several distinct rolling mills which have come into widespread use throughout the industry. These mills include the two-high mill, the fourhigh rnill and the cluster type Z-mill. The Z-mill, which is the subject matter of various inventions disclosed in U.S. Patent Numbers 2,776,586 and 3,214,952 by way of example, have distinct advantages over the two-high and four-high mills. The two-high and four-high mills employ simple drives, but suffer from lack of adequate control of the working operations and control over the contour of the workpiece, among other things. The latter mills are therefore usually limited in their application to the rolling of strip and sheet where precision is not a prime requirement. The Z-mill has several advantages, including the use of a one piece frame, the ability to employ small work rolls to adequately control the working operations and the contour of the finished work. As such, the Z-mill is useful in making carefully controlled reductions, or even moderately heavy reductions While producing finished work of high quality.

In the Z-mill or cluster mill, as it is sometimes referred to, there are 12 rolls arranged in a unitary housing. As such, there is a limitation in the work roll sizes that may be employed in a given mill. In addition, the conventional Z-mill arrangement utilizes several small drive rolls which are not in line and therefore this mill requires a distinct pinion stand and drive as compared to the stands and drives employed for the conventional twoand four-high mills. Additionally, for a given size of back-up rolls, the arrangement and design is such, that the Z-mill does not lend itself for adaption and use in the conventional twoand four-high mill stand.

Finally, in connection with the Z-mill or other conventonal cluster mills, the design of the mills and arrangement of the rolls are such that the back-up rolls are in contact with more than one roll. Accordingly, when one roll jams and the other continues to rotate, the resultant skidding on the back-up roll can cause serious damage to the roll or rolls. In the design and arrangement of Patented Aug. 19, 1969 ICC the instant invention this disadvantage is eliminated due to the fact that there is only one line of contact for each of the back-up rolls.

In View of the foregoing, the present invention is directed to a new mill of the cluster type which overcomes most, if not all of the disadvantages, outlined above and, in addition, permits the use of .a wide range of roll sizes. This is accomplished by a new cluster arrangement employing eight rolls in a novel fashion, which arrangement contemplates the use of drive rolls which are in line with the work rolls and which drive the Work rolls through the intermediate rolls. Primary and auxiliary back-up rolls are provided for the drive rolls and intermediate rolls and these back-up rolls complete the cluster. In the preferred embodiment shown herein the rolls are arranged in chocks similar to those employed in the conventional two-high and four-high mills thereby permitting an easy interchange with the conventional twoand fourhigh mill stands. It is understood of course that a solid housing similar to the one piece Z-mill housing can be employed.

In view of the foregoing, it is an object of this invention to provide a new cluster mill arrangement.

Another object of the invention is to provide a new cluster mill arrangement which employs considerably less rolls than the conventional cluster mill .and which can employ a relatively wide range of work roll sizes.

Still another object of the invention is to provide a new cluster mill arrangement which may be used with the conventional mill stands and which is equally adaptable for use with the conventional twoand four-high drive and pinion stands.

A still further object of the invention is to provide a new cluster mill arrangement which can be interchanged in the conventional two-high and four-high mill stand by an interchange of chocks and rolls.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exempliiied in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a plan view of a drive and cluster mill arrangement in accordance with a preferred embodiment of the instant invention;

FIG. 2 is a side elevational View of the drive and cluster mill shown in FIG. 1;

FIG. 3 is a partial cross-sectional view taken along line 3 3 of FIG. 2;

FIG. 4 is an enlarged view of the chock and roll cluster arrangement of FIG. 3;

FIG. 5 is a perspective view of the upper chock shown in FIG. 2;

F-IG. 6 is an elevational view of a modified form of the roll cluster shown in FIGS. 3 and 4; and

FIG. 7 is an elevational view of a mill .stand showing a conventional four-high or two-high mill arrangement.

Referring now to FIGS. 1 and 2 there is shown a drive motor 11 which is connected to a conventional pinion stand and speed reducer 12 through a shaft and coupling arrangement generally indicated at 13. The particular pinion stand 12, which forms no part of the instant invention, is provided with a pinion gear 14 which drives upper and lower gears `15 and 16 through an intermediate gear 17. As such, the intermediate gear 17 drives the lower roll gear 16 and the lower roll gear 16 drives the upper 3 roll gear 15. In this manner the necessary speed reductions are effected and the two roll gears are driven in the opposite directions so as to bring about the proper rotation of the drive rolls.

The upper and lower roll gears and 16 are coupled to upper and lower drive shafts 18 and 19 respectively by suitable flexible coupling devices generally indicated at 20. These flexible coupling devices are so chosen that they can effect a positive roational drive to upper and lower drive rolls 21 and 22 respectively, without the necessity of being in line with the axis of rotation of the drive rolls. In this particular arrangement (circumferential) female and male gear tooth arrangements were employed, Vbut it is to be understood that any comparable coupling may be employed for the purpose, so long as movement of the upper and lower drive shafts 18 and 19 may be shifted as generally indicated by the arrows in FIG. 2, to adapt to different drive roll sizes, etc.

Referring specifically to FIGS. 2 and 3, there is shown a mill stand 23, which is provided with a window or opening 24 in which upper and lower chocks 25 and 26 are slidably mounted. The mill stand 23 may be provided with a conventional screwdown device 27 which helps to set the effective nip and pressure of the upper and lower work rolls 28 and 29, respectively.

Referring now to FIGS. 3 and 4, the cluster arrangement of the instant invention is seen to comprise the single drive rolls 21 and 22 which are in vertical alignment with the work rolls 28 and 29, respectively. The upper and lower work rolls 28 and 29 are frictionally driven by upper and lower intermediate rolls, such as upper right intermediate roll 30, upper left intermediate roll 31, lower right intermediate roll 32 and lower left intermediate roll 33. The upper right intermediate roll 3i) is in contact with an upper right back-up roll 34, while upper left intermediate roll 31 is in contact with an upper left back-up roll 35. in the same fashion lower right intermediate roll 32 is in contact with a lower right back-up roll 36, while lower left intermediate roll 33 is in contact with a lower left back-up roll 37. It is understood, of course, for purposes of presenting a workable arrangement that the upper and lower back-up rolls 34, 35, 36 and 37, respectively, are not in contact with the upper and lower drive rolls 21 and 22. The cluster of this invention further includes a pair of upper and lower auxiliary backup rolls which comprise an upper right auxiliary back-up roll 38, an upper left auxiliary back-up roll 39, a lower right auxiliary back-up roll 40 and a lower left auxiliary back-up roll 41. These rolls are in frictional contact with the drive rolls and help provide further stability and control over the other rolls in the cluster. It is also to be understood, of course, that the back-up rolls may be of the solid type or, where desirable, of the so-called interdigitated type as illustrated, for example, in U.S. Patent No. 3,214,952.

Referring now to FIG. 5, the upper chock 25, which is similar to the lower chock 26, is constructed as a unitary member according to the preferred embodiment of the invention and includes bearing bosses 42 and 43 which engage the screwdown devices 27 in a conventional manner. The chocks of course are provided with a scalloped contour at 44, so as to provide the necessary clearance for the various rolls in the cluster. The back-up support mechanism (not shown) for the split chocks is of the general type used in cluster mills and employs collars 45 to support the back-up rolls intermediate their length in much the same fashion as the support for the back-up rolls shown in U.S. Patent No. 2,776,586, which discloses one particular chock and back-up roll arrangement. It is to be understood of course that any other comparable and well known arrangement may be employed for this purpose. As such, the upper and lower chocks 25 and 26 each may be formed in two parts and thus support the rolls at their ends or journals.

As is customary, stock is fed between the work rolls 28 and 29 and, depending upon the screwdown provided through the screwdo-wn devices 27 to the chocks 25 and 26, a particular pressure and nip is experienced at the work rolls by the stock. The rotation of the drive ro-lls 21 and 22 by the appropriate rotation of the drive shafts 18 and 19 effects a compatible rotation of the intermediate rolls 3G, 31, 32 and 33 as well as the work rolls 28 and 29 and the auxiliary back-up rolls 3S, 39, 40 and 41. By the same token a compatible rotation is effected for the back-up rolls 34, 35, 36 and 37 through the intermediate rolls 30, 31, 32 and 33. As such, it is evident that the cluster acts as a unit to provide the necessary control over the rolling of stock into sheet or strip, as the case may be.

Referring now to FIG. 6, there is shown a modification of the cluster mill arrangement shown in FIGS. l through 4. In this particular arrangement the upper and lower work rolls and 47, respectively, are much larger than the upper and lower work rolls 2S and 29, while the upper and lower right and left intermediate rolls 48, 49, and 51 are smaller. The same may be the case for the upper and lower drive rolls 52 and 53, respectively. The upper and lower back-up rolls and the upper and lower auxiliary back-up rolls can be, however, of the same size. As such, it is evident that there is provided great latitude in the size of the work rolls that may be employed with a minimum amount of change in the drive rolls and intermediate rolls. This, by way of illustration and example, is not the case for a conventional cluster mill where an entire new cluster arrangement including chock, back-up rolls, intermediate rolls and work rolls must be changed in order to go to an appreciably larger work roll size. In addition, it would be necessary to change at least the size of 5 rolls due to the fact that there are in essence 3 drive rolls in a conventional cluster mill, while only three rolls need be changed in the mill according to the instant invention.

As illustrated in FIG. 6, the axis of rotation of the upper and lower back-up rolls 34, 35, 36 and 37, respectively, are positioned slightly above the axis of rotation of the upper and lower intermediate rolls 48, 49, 50 and 51. This positioning of the axis is necessary to maintain a vertical pressure on the intermediate rolls. The same holds true for the upper and lower auxiliary back-up rolls 38, 39, 40 and 41, respectively, whose axes are above the axis of the work roll axis.

As can be seen, the configuration according to the instant invention has several distinct advantages in that it possesses the same basic in-line drive as the conventional twoand four-high mills and it can be accommodated in the same stand as the basic twoand four-high mill arrangements. This can all be accomplished without altering the drive and without the necessity of providing a complicated drive mechanism as is necessary when employing the conventional cluster or Z-mill. This is primarily accomplished by the novel cluster mill and chock arrangement.

In FIG. 7 there is shown a conventional four-high mill with upper and lower back-up rolls 54 and 55, respectively. These bear against upper and lower work rolls 56 and 57 in the conventional four-high arrangement. Assuming the mill to be a two-high mill, say, by eliminating rolls 56 and 57, the rolls 54 and 55 are the work rolls and, of course, being the only rolls, are also the drive rolls. In either case the drive is in vertical alignment. This is also the case for the new cluster mill arrangement of the instant invention and accounts for the versatility of the new cluster and chock arrangement which is adaptable to the conventional two-high and four-high mill stand as well as the conventional twoand four-high mill drive.

The new mill according to the instant invention has substantially almost all of the advantages of the so-called conventional cluster mills in that the loads are distributed over four back-up rolls which are assembled in the upper and lower chocks. The upper and lower back-up rolls act to distribute the load on the upper and lower intermediate rolls, while the upper and lower auxiliary back-up rolls act to distribute the load of the work rolls 28, 29 (or 46 and 47) as the case may be.

The rolls in the new cluster mill are arranged in a compact fashion for use in the conventional twoand fourhigh mill stands and can be driven in a conventional manner from the conventional twoor four-high mill drive. The extra rolls (over and above those employed in the conventional two-high and tour-high mills) arranged as such provide the extra stability and control which is of course absent in the conventional twoand four-high mills.

Finally, while it is illustrated (according to a preferred embodiment of the invention) that the rolls 21 and 2-2 or the rolls 52 and 53 are the drive rolls, it is to be understood that the work rolls 28 and 29 or 46 and 47 could be employed as both drive and work rolls while still employing the conventional lfour-high or two-high mill drive.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A cluster mill arrangement whose Work roll sizes may be interchanged without the necessity of changing the mill housing or drive stand, consisting of in combination, upper and lower work rolls, a pair of upper and lower intermediate rolls in contact with said upper and lower work rolls, a pair of main back-up rolls in contact with said upper and lower intermediate rolls, upper and lower center rolls in contact with said upper and lower intermediate rolls, a pair of auxiliary back-up rolls in contact with said upper and lower center rolls, and means for maintaining said rolls in a cluster arrangement, whereby the loads produced during rolling are distributed over a plurality of rolls.

2. The cluster mill arrangement of claim 1, further defined in that the axis of said main back-up rolls are disposed at a greater distance from the line of pass of the work as compared to the axis of the said intermediate rolls.

3. The cluster mill arrangement of claim 2, further defined in that the axes of said auxiliary back-up rolls are disposed at a greater distance from the line of pass of the work as compared to the axis of the said center rolls.

4. The cluster mill arrangement of claim 1, wherein said means for maintaining said rolls in a cluster arrangement comprises a pair of chocks contained within a mill stand.

5. The cluster mill arrangement of claim 1, further defined in that said work rolls are driven.

6. A cluster mill arrangement useful in the rolling of sheet or strip from stock, whose stock contacting roll sizes may be interchanged without the necessity for changing the mill housing or drive stand, consisting of in combination, a pair of stock contacting rolls, two pairs of intermediate rolls, each intermediate roll pair in contact with said stock contacting rolls, two pairs of back-up rolls, each back-up roll in contact with a corresponding intermediate roll, a pair of center rolls, each one in contact with each pair of intermediate rolls, and two pairs of auxiliary back-up rolls in contact with said pair of center rolls.

7. The cluster mill arranged of claim 6, further defined in that said stock contacting rolls are driven.

8. The cluster mill arrangement of claim 1 further dened in that the means for maintaining said rolls in a cluster includes a solid housing.

9. The cluster mill arrangement of claim l, further defined in that said center rolls are driven.

10. The cluster mill arrangement of claim 6, further defined in that said center rolls are driven.

References Cited UNITED STATES PATENTS 1,071,846 9/ 1913 Wilmot 72-242 2,368,030 1/ 1945 Larsson 72-242 2,479,974 8/ 1949 Sendzimir et al 72--249 2,776,586 1/ 1957 Sendzimin 72-242 3,076,360 2/ 1963 Sendzimir 72-242 3,128,650 4/ 1964 Leufvn 72,-242 3,169,423 2/ 1965 Sims 72--242 3,178,919 4/1965 Varner 72-242 MILTON S. MEHR, Primary Examiner 

